Differential Subcellular Localization of the Splice Variants of the Zinc Transporter ZnT5 Is Dictated by the Different C-Terminal Regions.
- Resource Type
- Article
- Authors
- Thornton, Jared K.; Taylor, Kathryn M.; Ford, Dianne; Valentine, Ruth A.
- Source
- PLoS ONE. 2011, Vol. 6 Issue 8, p1-10. 10p.
- Subject
- *ZINC transporters
*CATALYTIC activity
*METALLOPROTEINS
*HOMEOSTASIS
*GOLGI apparatus
*EXONS (Genetics)
*ENDOPLASMIC reticulum
*MOLECULAR dynamics
- Language
- ISSN
- 1932-6203
Background: Zinc is emerging as an important intracellular signaling molecule, as well as fulfilling essential structural and catalytic functions through incorporation in a myriad of zinc metalloproteins so it is important to elucidate the molecular mechanisms of zinc homeostasis, including the subcellular localizations of zinc transporters. Principal Findings: Two splice variants of the human SLC30A5 Zn transporter gene (ZnT5) have been reported in the literature. These variants differ at their N- and C-terminal regions, corresponding with the use of different 59 and 39 exons. We demonstrate that full length human ZnT5 variant B is a genuine transcript in human intestinal cells and confirm expression of both variant A and variant B in a range of untreated human tissues by splice variant-specific RT-PCR. Using Nor C-terminal GFP or FLAG fusions of both isoforms of ZnT5 we identify that the differential subcellular localization to the Golgi apparatus and ER respectively is a function of their alternative C-terminal sequences. These different C-terminal regions result from the incorporation into the mature transcript of either the whole of exon 14 (variant B) or only the 59 region of exon 14 plus exons 15-17 (variant A). Conclusions: We thus propose that exons 15 to 17 include a signal that results in trafficking of ZnT5 to the Golgi apparatus and that the 39 end of exon 14 includes a signal that leads to retention in the ER. [ABSTRACT FROM AUTHOR]